Wavelength division multiplexing (WDM) is an optical technology that aggregates many wavelengths for transmission on the same fiber. To maximize bandwidth usage, lower bit rate data signals are often aggregated onto each wavelength. However, conventional architectures do not facilitate cost effective use of the entire available bandwidth.
Optical transport systems typically employ line cards adapted to receive one or more client input signals and output an optical transport signal. In such known architectures, each line card is designed for a specific type of protocol or data rate. In other words, architectures having different configurations require the use of different types of line cards. It should also be noted that client input signals having different protocols and/or different data rates are typically transmitted on different wavelengths.
Therefore, it is desirable to provide a line card that aggregates client signals having different protocols and/or different data rates. The line card should be in-service reconfigurable via the use of modular client-specific tributary cards that are accessible from the front panel of the line card. Since tributary cards can be modularly built using different transceivers, service providers can reduce line card inventory levels. It is also advantageous for the line card to asynchronously output an optical system signal independently from the availability of client signal. In this way, the client-specific tributary cards may be hot-swappable without affecting the transmission of the optical system signal.